Electric lamp



March 6, 1928.

w. DAWSON ELECTRIC LAMP Filed May 25. 1927 A TTORMEY Patented Mar. 6, 1928.

UNITED STATES wrrrann DAWSON, or LONDON, nnonann.

ELECTRIC LAMP.

Application filed Kay 28, 1927, Serial No. 193,587, and in Great Britain June 16, 1926.

This invention relates to electric lamps of the filament type and is applicable both to the vacuum and gas filled lamps.

The primary object of the invention is to provide a lamp of the multiple filament type having a continuous filament so shaped and connected up that successive portions are in the form of loops or sections arranged one above the other in the different planes.

By the word loop is meant a closed or nearly closed curve.

An advantage of this construction is that each 100 may form a nearly complete circle and t at the different loops may bear the same relation to the central axis of the lamp.

In one arrangement three sections of fila ment may be provided and four leading-in wires are connected to the filament sections so that one or other of the sections can be illuminated. In another arrangement, we have two sections of filament and three leading-in wires. The sections may be of difierent or the same length so that by varying the connections of the leading-in wires to 26 the supply wires by means of a separate switch or rotary movement of the cap in the holder a considerable variation in intensity of light is possible, or the same intensity of light may be obtained by the alternative 80 use of the different sections.

With the above and other objects in view the invention consists in the constructions hereinafter described and set out in the accompanying claims.

The accompanying drawing illustrating an embodiment of the invention represents the lower portion of a lamp constructed in accordance with the invention andhaving a filament in three sections connected to four 40 leading-in wires.

Referring now to the drawing the filament sections a, b, c, are shown as of arcuate form; they are one above the other in difi'erent planes and with the exception of short conmeeting portions are similar loops in parallel planes bearing the same relation to the central axis. One end of the upper filament section a is connected to a leading-in wire g and the other end is connected to a leading-in wire 7 and also to the intermediate filament section b the other end of which is connected to a leading-in wire 9 and the lower filament section 0 is connected at one end to the filament b at its point of connection to the leading-in wire 0, and at the other end to the leading-in wire d.

The filament illustrated is of spirallywound form and is supported by a series of support wires 7' which radiate in the planes of the loops from the central support stem g of glass or other insulating material.

By selectively connecting the leading-in wires to the. source of electric supply the current can be caused to flow separately through any one of the filament sections.

I claim:

1. A multiple filament electric lamp having in combination a continuous filament divlded into a plurality of sections in substantially parallel planes, and leading-in wires connected to each end of the filament and to points at the end of each intermediate section of the filament.

2. A multiple filament electric lamp havmg in combination a continuous filament divided into a plurality of sections of arcuate form in different planes, and leading in wires connected to each end of the filament and to points at the end of each intermediate section of the filament.

3. An electric lamp having in combination a continuous'filament divided into a plurality of sections in substantially parallel planes, a central support stem of insulating material, radiating support wires passing from the support stem to each parallel filament section and leading-in wires connected to each end of the filament and to points at the end of each intermediate section of the filament.

' 4:. A multiple filament electric lamp having in combination a continuous filament divided into a plurality of sections, such sections forming, with the necessary interconnecting portions, a series of loops in parallel planes, and leading-in wires connected to each end of the filament and to points forming the junctions of the various sections of the filament.

5. A multiple filament electric lamp having in combination a continuous filament divided into a plurality of sections of arcuate form in diflerent planes, a central support stem of insulating material, radiating support wires passing from the support stem to each parallel filament section and leading-in wires connected to each end of the filament and to points at the end of each intermediate section of the filament.

6. A multiple filament electric lamp having in combination a continuous filament divided into a plurality of sections in substan- (ill tially parallel planes, a central support stem of insulating material, radiating support wires passing from the support stem to each parallel filament section and leading-1n wires connected to each end of the filament and to points at the end of each intermediate section of the filament.

7. A multiple filament lamp having in combination a continuous filament divided into a pluraltiy of sections, such sections forming, with the necessary interconnecting portions a series of loops in parallel planes, a central support stem of insulating material, a series of radiating wires passing from the central support stem in the plane of each loop and engaging each filament loop, and leadingin wires connected to each end of the filament and to the points forming the junctions of the various sections of the filament.

8. A multiple filament electric lamp having in combinatioira continuous spirallywound filament divided into a plurality of sections in substantially parallel planes, and leading-in wires connected to each end of the filament and to points at the end of each intermediate section of the filament.

In testimony whereof I afiix my signature.

WILFRED DAWSON. 

